Periodic Table/Thorium
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90Th232.0377 Da

Thorium

Actinide·Period 7·f-block

Grey radioactive metallic element. Belongs to actinoids. Found in monazite sand in Brazil, India and the US. Thorium-232 has a half-life of 1.39x10^10 years. Can be used as a nuclear fuel for breeder reactors. Thorium-232 captures slow Neutrons and breeds uranium-233. Discovered by Jons J. Berzelius in 1829.

Gallery

Thorium Metal in Ampoule, corroded

W. Oelen, CC BY-SA 3.0 <https://creativecommons.org/licenses/by-sa/3.0>, via Wikimedia Commons

Bohr model of Thorium

Physical Propertiesmass · density · phase · crystal

Atomic Mass

232.0377Da

Density

11.7000g/cm³

Phase (STP)

Solid

Melting Point

2023.2K

Boiling Point

5058.1K

Molar Heat

0.1180J/(mol·K)

Crystal Structure

FCC

Lattice Constant

5.080Å

Atomic Radiiatomic · covalent · van der Waals

Atomic (Empirical)

180.00pm

Covalent

175.00pm

Van der Waals

245.00pm

Electronic Propertieselectronegativity · ionization · affinity

Electron Configuration

[Rn] 6d2 7s2

Electron Shells

2, 8, 18, 32, 18, 10, 2

Electronegativity

1.30Pauling

Electron Affinity

—

1st Ionization Energy

6.3kJ/mol

Oxidation States

+2, +3, +4

Orbital DiagramAufbau · Hund's rule · Pauli exclusion

↑↓
1s2
↑↓
2s2
↑↓
↑↓
↑↓
2p6
↑↓
3s2
↑↓
↑↓
↑↓
3p6
↑↓
↑↓
↑↓
↑↓
↑↓
3d10
↑↓
4s2
↑↓
↑↓
↑↓
4p6
↑↓
↑↓
↑↓
↑↓
↑↓
4d10
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
↑↓
4f14
↑↓
5s2
↑↓
↑↓
↑↓
5p6
↑↓
↑↓
↑↓
↑↓
↑↓
5d10
↑↓
6s2
↑↓
↑↓
↑↓
6p6
↑
↑
6d2
↑↓
7s2

Full: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 4f14 5s2 5p6 5d10 6s2 6p6 6d2 7s2Short: [Rn] 6d2 7s2

Ionization Energies (90 known)

1st6.3 kJ/mol2nd12.1 kJ/mol3rd18.3 kJ/mol4th28.6 kJ/mol5th58.0 kJ/mol6th69.1 kJ/mol7th82.0 kJ/mol8th95.0 kJ/mol9th118.0 kJ/mol10th133.0 kJ/mol11th165.0 kJ/mol12th181.0 kJ/mol13th262.0 kJ/mol14th285.0 kJ/mol15th310.0 kJ/mol16th336.0 kJ/mol17th362.0 kJ/mol18th389.0 kJ/mol19th424.0 kJ/mol20th451.0 kJ/mol21th480.0 kJ/mol22th508.0 kJ/mol23th650.0 kJ/mol24th680.0 kJ/mol25th720.0 kJ/mol26th750.0 kJ/mol27th830.0 kJ/mol28th870.0 kJ/mol29th970.0 kJ/mol30th1010.0 kJ/mol31th1090.0 kJ/mol32th1160.0 kJ/mol33th1240.0 kJ/mol34th1310.0 kJ/mol35th1380.0 kJ/mol36th1460.0 kJ/mol37th1530.0 kJ/mol38th1600.0 kJ/mol39th1680.0 kJ/mol40th1760.0 kJ/mol41th1830.0 kJ/mol42th1910.0 kJ/mol43th1980.0 kJ/mol44th2060.0 kJ/mol45th2390.0 kJ/mol46th2455.0 kJ/mol47th2524.0 kJ/mol48th2598.0 kJ/mol49th2669.0 kJ/mol50th2737.0 kJ/mol51th2864.0 kJ/mol52th2935.0 kJ/mol53th3013.0 kJ/mol54th3086.0 kJ/mol55th3375.0 kJ/mol56th3445.0 kJ/mol57th3522.0 kJ/mol58th3593.0 kJ/mol59th3943.0 kJ/mol60th4025.0 kJ/mol61th4230.0 kJ/mol62th4313.0 kJ/mol63th6972.0 kJ/mol64th7130.0 kJ/mol65th7299.0 kJ/mol66th7480.0 kJ/mol67th7650.0 kJ/mol68th7810.0 kJ/mol69th8180.0 kJ/mol70th8350.0 kJ/mol71th8550.0 kJ/mol72th8720.0 kJ/mol73th9220.0 kJ/mol74th9370.0 kJ/mol75th9540.0 kJ/mol76th9690.0 kJ/mol77th10790.0 kJ/mol78th10970.0 kJ/mol79th11340.0 kJ/mol80th11510.0 kJ/mol81th24060.0 kJ/mol82th24480.0 kJ/mol83th24940.0 kJ/mol84th25360.0 kJ/mol85th29410.0 kJ/mol86th29970.0 kJ/mol87th30680.0 kJ/mol88th31122.8 kJ/mol89th123091.0 kJ/mol90th125250.3 kJ/molSuccessive Ionization Energies

Emission Spectrumvisible range · characteristic spectral lines

402
422
453
Th emission
380nm750nm
401.9 nm(100%)421.7 nm(60%)453.4 nm(40%)

Abundanceby mass

🌍Earth's Crust
9.6 ppm
🌊Ocean
1.0 ppt
✨Universe
400.0 ppt
🧬Human Body—

Log scale · ppm = parts per million by mass

Biological Role

Toxic

Weakly radioactive. Can cause liver and bone damage if inhaled or ingested.

Discovery

Discovered By

Jöns Berzelius

Named By

—

Year

1828

Nuclear Data

Known Isotopes

32

Stable Isotopes

0

Stable Mass Numbers

None

Natural isotopic abundance (IUPAC recommended values)

Isotopes of Th32 known

NuclideZNMass (AMU)Half-lifeDecayJπAbundance
208Th90118208.0179152.40 msα (1%)0+—
209Th90119209.017601Unknownα, β⁺5/2-—
210Th90120210.01509416.0 msα (1%), β⁺0+—
230Th90140230.03313275.4 kyα (1%), SF (0.04%), 24Ne (0.057999999999999996%)0+2.0000%
232Th90142232.03805414.0 Gyα (1%), SF (0.011000000000000001%), 26Ne (0.0278%), 2β⁻0+9998.0000%
237Th90147237.0536294.80 minβ⁻ (1%)5/2+—
238Th90148238.0563889.40 minβ⁻ (1%)0+—
239Th90149239.060655Unknownβ⁻7/2+—

Click any isotope for its full page with decay chain:

208Th209Th210Th211Th212Th213Th214Th215Th216Th217Th218Th219Th220Th221Th222Th223Th224Th225Th226Th227Th228Th229Th230Th231Th232Th233Th234Th235Th236Th237Th238Th239Th
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